mattermost-community/focalboard · error

unable to create session

Error message

unable to create session

What it means

Login wraps an error from store.CreateSession as 'unable to create session'. After user/password validation succeeds, the app persists a new Session (ID, token, userID) to the store; if that write fails, login cannot issue a token and this wrapped error is returned. It indicates a storage-layer problem, not an authentication problem.

Source

Thrown at server/app/auth.go:125

		a.logger.Debug("Invalid password for user", mlog.String("userID", user.ID))
		return "", errors.New("invalid username or password")
	}

	authService := user.AuthService
	if authService == "" {
		authService = "native"
	}

	session := model.Session{
		ID:          utils.NewID(utils.IDTypeSession),
		Token:       utils.NewID(utils.IDTypeToken),
		UserID:      user.ID,
		AuthService: authService,
		Props:       map[string]interface{}{},
	}
	err := a.store.CreateSession(&session)
	if err != nil {
		return "", errors.Wrap(err, "unable to create session")
	}

	a.metrics.IncrementLoginCount(1)

	// TODO: MFA verification
	return session.Token, nil
}

// Logout invalidates the user session.
func (a *App) Logout(sessionID string) error {
	err := a.store.DeleteSession(sessionID)
	if err != nil {
		return errors.Wrap(err, "unable to delete the session")
	}

	a.metrics.IncrementLogoutCount(1)

	return nil

View on GitHub (pinned to a84bbb65e3)

Solutions

1. Inspect the wrapped cause for the store's underlying write error
2. Check DB health: disk space, connection limits, sessions table exists and is migrated
3. Retry the login once the storage backend recovers
4. If a corrupted/partial session row conflicts, delete the stale session row and retry

Example fix

// before
// ignoring wrapped cause makes diagnosis hard
return err
// after
if err != nil {
    log.Errorf("create session failed: %v", errors.Cause(err))
    if isRetryable(errors.Cause(err)) {
        time.Sleep(500 * time.Millisecond)
        return a.Login(username, email, password, mfaToken) // retry once
    }
    return err
}

// Confirm store writability before login
if err := store.Ping(); err != nil {
    return fmt.Errorf("store not ready for sessions: %w", err)
}

func isRetryableStoreErr(err error) bool {
    c := errors.Cause(err)
    return errors.Is(c, sql.ErrConnDone) || errors.Is(c, driver.ErrBadConn)
}

token, err := app.Login(username, email, password, "")
if err != nil && strings.Contains(err.Error(), "unable to create session") {
    time.Sleep(backoff)
    token, err = app.Login(username, email, password, "") // retry once
}

When it happens

Trigger: App.Login with valid credentials where a.store.CreateSession returns an error: DB write failure, constraint violation on the sessions table, store closed/locked, or storage backend outage.

Common situations: Database disk full; sessions table missing/corrupted after partial migration; DB connection pool exhausted; store write permissions or replication issues.

Related errors

• insertBoard error occurred while fetching existing board %s:
• unable to delete the session
• ErrorId.NotLoggedIn
• card limit value is invalid
• database type is unsupported

AI-assisted analysis of mattermost-community/focalboard@a84bbb65e3 (2026-08-30). Data as JSON: /api/errors/7e1f0eb90cffd0b9. Report an issue: GitHub.